Overall modification, polymer materials

Modification of polymer materials has a very broad meaning. In the modification process, both physical and chemical changes can take place. Because of the perplexing relationship between the structure and properties of polymeric materials, when one method is used to improve a certain kind of performance, other properties may also change. Therefore, in the modification practice, extra multiple impacts of some valuable properties of polymer materials must be prevented, and an overall balance should be sought among the conflicting effects.3 5... 

Overall modification is the modification that occurs in both the interior and the surface of the polymer material. A feature of this kind of modification is that performance changes uniformly. Modification of polymer materials is mostly overall modification, such as filling modification, blending modification, crosslinking modification, morphology control modification, and so forth that were mentioned previously. 

Among the various radiation-induced modifications, the EB-processing of polymers has gained special importance as it requires less energy, is simple, fast, and versatile in application. The overall properties of EB-irradiated polymeric materials are also improved compared to those induced by other ionizing radiation. 

The modification of PET with naphthalene-2,6-dicarboxylic acid and other additional comonomers is a common measure in bottle manufacturing. Copolyesters based on this compound show excellent barrier properties. Such materials can be produced by addition of the desired amount of comonomer during polymer processing or by blending PET with poly(ethylene naphthalate) (PEN). Additionally, PEN can also be modified by other comonomers such as isophthalic acid (IPA) to improve the flow properties and reduce the melting point. The high price of naphthalene dicarboxylic acid is the reason for its limited application. The overall cost may be reduced by using TPA or IPA as comonomers. 

Chemical modification reactions continue to play a dominant role in improving the overall utilization of lignocellulosic materials [1,2]. The nature of modification may vary from mild pretreatment of wood with alkali or sulfite as used in the production of mechanical pulp fibers [3] to a variety of etherification, esterification, or copolymerization processes applied in the preparation of wood- [4], cellulose- [5] or lignin- [6] based materials. Since the modification of wood polymers is generally conducted in a heterogeneous system, the apparent reactivity would be influenced by both the chemical and the physical nature of the substrate as well as of the reactant molecules involved. 

Oxadiazoles experienced an almost 80-year long period of scientific lethargy before they tickled the curiosity of chemists. The study of chemical and photochemical reactivity of 1,2,4-oxadiazoles opened the way to a series of applications in heterocyclic synthesis. Today, 1,2,4-oxadiazoles are known in medicinal chemistry for their use as bioisosters of esters and amides. Furthermore, fluorinated 1,2,4-oxadiazoles have been applied in materials science either by themselves or for the targeted modification of polymers and macromolecules. Overall, the synthesis of... 

The advantage of the latter reactions is that they are generally applicable to a variety of proteins, synthetic polymers and plasma-treated surfaces [82]. The overall surface density of the peptides can also be eontrolled easily via these chemical modification strategies, which can have a large impaet on eell proliferation and differentiation, particularly when coupled with manipulation of the chemical composition of the matrix material [85]. 

---